CAMSTRA, Hans Willem (Holterweg 123, EK Doetinchem, NL-7001, NL)
| Claims 1. Device for sorting a mixture of waste paper, comprising a conveyor belt (1 ) disposed at an incline and provided with drive means (2), supply means (3) for placing the paper mixture on the low outer end of the conveyor belt and blowing means (4) placed close to the high outer end of the conveyor belt, characterized in that the drive means are adapted to drive the conveyor belt at a speed of at least 3 metres per second. 2. Device as claimed in claim 1, characterized in that the drive means (2) are dimensioned such that the conveyor belt (1) transports books and heavier magazines in the paper mixture at a speed of 3-8 metres per second. 3. Device as claimed in claim 1 or 2, characterized in that the blowing means comprise a fan (4) with a large surface area placed lower than the high outer end of the conveyor belt (1), in addition to an air knife (9). 4. Device as claimed in claim 3, characterized in that the air knife (9) is placed lower than the high outer end of the conveyor belt (1 ). 5. Device as claimed in claim 3 or 4, characterized in that the air knife (9) comprises a closing means (10) plus control means (11) for pulsed operation of the air knife. 6. Device as claimed in claim 5, characterized in that the device also comprises detector means (12) for detecting an object lying on the conveyor belt (1) close to the high outer end, wherein the detector means are connected to the control means (11) for the purpose of activating the air knife (9). 7. Device as claimed in claim 6, characterized in that the control means are adapted to briefly open the closing means (10) at the moment that a highest outer end or a lowest outer end of the object leaves or has just left the conveyor belt (1 ). 8. Device as claimed in claim 7, characterized in that the air knife comprises a row of separate nozzles (9a, 9b, 9c, 9d), wherein the detector means comprise a row of separate detectors (12a, 12b, 12c, 12d), each provided with a closing means (10), and wherein the control means (11) are adapted to briefly open the closing means (10) at the moment that the associated detector detects a highest outer end or a lowest outer end of the object. 9. Device as claimed in any of the foregoing claims, characterized in that the device is provided with additional blowing means and/or suction means (8) placed close to at least a side of the conveyor belt (1) and/or at least substantially centrally above the conveyor belt. 10. Device as claimed in any of the foregoing claims, characterized in that the conveyor belt (1 ) is provided with transverse ribs (7). 11. Method for sorting waste paper making use of a device as claimed in any of the foregoing claims. |
The invention relates to a device for sorting a mixture of waste paper, comprising a conveyor belt disposed at an incline and provided with drive means, supply means for placing the mixture on the low outer end of the conveyor belt and blowing means placed close to the high outer end of the conveyor belt.
Devices of this type are known. They are used to separate supplied waste paper into a number of fractions, which can then be marketed separately. It is the case here that the price is determined to a significant extent by the homogeneity within the supplied fraction, the quality as such and the absence of non-paper fractions. This is related to the fact that the buyer, generally a paper supplier and/or manufacturer, must deliver a constant quality. For this purpose he has to know as precisely as possible the quality and the properties of the presented batches of paper. In known devices a paper mixture is carried upward by the conveyor belt, after which it is allowed to drop downward. The blowing means disperse the falling paper, wherein more compact components will be scattered less far than loose sheets and lightweight leaflets. The speed of the conveyor belt is chosen here such that the paper is not blown upward from the conveyor belt, and is about 2 metres per second.
A drawback of the known devices is that they are all but incapable of separating leaflets, newspapers and magazines from each other. Leaflets, newspapers and magazines from a compact component which is hardly dispersed by the blowing means. This is particularly the case with newspapers in folded form, which are then very similar to magazines.
The device according to the invention is more particularly intended to sort a mixture of mainly loose sheets, leaflets, newspapers and magazines, and has the feature that the drive means are adapted to drive the conveyor belt at a speed of at least 3 metres per second. The relatively high speed has the result here that a loose sheet will be blown upward quickly and a leaflet, newspaper or magazine will begin to roll about as soon as it makes contact with the conveyor belt, whereby there is great chance of the leaflet and/or newspaper partially blowing open and thereby acquiring a relatively large surface area. When a magazine blows open the increase in the effective surface area in relation to the weight is limited. The result is that the blowing means will catch more of a leaflet and newspaper which has blown open, and will thus blow it relatively far away.
The drive means are preferably dimensioned such that the conveyor belt transports books and heavier magazines in the paper mixture at a speed of 3-8 metres per second. As a result of this relatively high speed leaflets, newspapers and lighter magazines will begin to roll about, whereby they will blow open.
A further favourable embodiment has the feature that the blowing means comprise a fan with a large surface area placed lower than the high outer end of the conveyor belt, in addition to an air knife. The fan here provides for the actual separation and the air knife ensures that a loose sheet, leaflet, newspaper or magazine will be tossed about again as it leaves the conveyor belt, whereby a leaflet and a newspaper can be blown further open so that there is an increased chance of the fan blowing the leaflet and the newspaper further away. The air knife is here preferably placed lower than the high outer end of the conveyor belt in order to prevent sheets which are blown upward from accumulating around and blocking the air knife. According to a further aspect of the invention, a very favourable embodiment has the feature that the air knife comprises a closing means plus control means for pulsed operation of the air knife. Only a part of a loose sheet, leaflet, newspaper or magazine is hereby struck by the airflow in each case, whereby particularly a leaflet, newspaper or magazine will be tossed about more violently.
A favourable embodiment which can significantly reduce the consumption of compressed air has the feature that the device also comprises detector means for detecting an object lying on the conveyor belt close to the high outer end, wherein the detector means are connected to the control means for the purpose of activating the air knife so that the air knife is activated only when a loose sheet, leaflet, newspaper or magazine approaches. The detector means can here consist simply of a light source plus a light-sensitive detector.
A very favourable embodiment, wherein the consumption of compressed air is reduced and wherein simultaneous rolling about of a leaflet, newspaper or magazine is optimized, has the feature that the control means are adapted to briefly open the closing means at the moment that a highest outer end or a lowest outer end of the object leaves or has just left the conveyor belt, and highly targeted contact is made with the paper in a predetermined area.
A very favourable embodiment, wherein the use of compressed air can be reduced still further and wherein simultaneous rolling about of a leaflet, newspaper or magazine is optimized, has the feature that the air knife comprises a row of separate nozzles, wherein the detector means comprise a row of separate detectors, each provided with a closing means, and wherein the control means are adapted to briefly open the closing means at the moment that the associated detector detects a highest outer end or a lowest outer end of the object.
A favourable embodiment, wherein the rolling about of leaflets, newspapers and magazines is intensified, has the feature that the conveyor belt is provided with transverse ribs which can cause extra rolling about of a falling leaflet, newspaper or magazine, whereby it can blow further open. An additional advantage is that, owing to the high speed of the conveyor belt, particularly a leaflet and/or newspaper tends to get left behind, this being counteracted by passing transverse ribs. Each passing rib here brings about an additional rolling about of a leaflet and/or newspaper, whereby it can blow further open. Heavier magazines will remain undisturbed on the conveyor belt, this being favourable for the final separation.
A very favourable embodiment has the feature that the device is provided with additional blowing means and/or suction means placed close to at least a side of the conveyor belt and/or at least substantially centrally above the conveyor belt, so that loose sheets and folders and newspapers which have blown open and/or have blown far enough open on the conveyor belt can already be removed at this stage of the process.
The invention also relates to a method for sorting waste paper making use of a device as specified in the foregoing paragraphs.
The invention will now be further elucidated with reference to the following figures, in which: Fig. 1 shows schematically a device for separating waste paper according to the prior art; Fig. 2 shows schematically a possible embodiment of a device for separating leaflets, newspapers and magazines according to the invention;
Fig. 3 shows schematically an alternative embodiment of a device for separating leaflets, newspapers and magazines according to the invention;
Fig. 4 shows schematically a further alternative embodiment of a device for separating leaflets, newspapers and magazines according to the invention;
Fig. 5 shows schematically a further alternative embodiment of a device for separating leaflets, newspapers and magazines according to the invention.
Fig. 1 shows schematically a device for separating waste paper according to the prior art, wherein substantially loose sheets and lightweight leaflets are separated from the rest. The device consists of a conveyor belt 1 disposed at an incline and provided with drive means 2 which are dimensioned such that conveyor belt 1 discharges the sheets, leaflets, newspapers and magazines at a speed of for instance 2 metres per second. The device further comprises a conveyor belt 3 for placing a mixture of different types of waste paper on the low outer end of conveyor belt 1 , and a fan 4 which is placed close to the high outer end of the conveyor belt and which blows apart waste paper falling from conveyor belt 1. Heavier leaflets, newspapers and magazines will here drop substantially straight downward and drop into a container 5. Loose sheets, very lightweight leaflets and a single sheet of newspaper will then drop into a container 6 disposed some distance from fan 4.
Because the fall behaviour of folded leaflets, newspapers and magazines differs little, a problem arises when further separation of the leaflets, newspapers and magazines is desired. Fig. 2 shows schematically a possible embodiment of a device for separating leaflets, newspapers and magazines according to the invention, which aims to change the fall behaviour of leaflets and newspapers by increasing the surface area thereof. The device consists of a conveyor belt 1 disposed at an incline and provided with drive means 2, a conveyor belt 3 for placing a mixture of leaflets, newspapers and magazines on the tow outer end of conveyor belt 1 , and a fan 4 which is placed close to the high outer end of the conveyor belt and which blows apart leaflets, newspapers and magazines falling from conveyor belt 1. Drive means 2 are dimensioned such that conveyor belt 1 transports the books and heavier magazines at a speed of 3-8 metres per second. As a result of this relatively high speed the leaflets, lighter newspapers and lighter magazines will begin to roll about, whereby they blow open. This effect can be enhanced by providing the conveyor belt with transverse ribs 7. At the moment that the leaflets, newspapers and magazines fall from conveyor belt 3 onto conveyor belt 1 , passing transverse ribs 7 will directly cause these leaflets, newspapers and magazines to roll about, this increasing the chance that the leaflets and newspapers will blow open. The result is that a part of the leaflets and newspapers has acquired a relatively large surface area at the top of conveyor belt 1. Using a fan 8 it is then possible to blow these leaflets and newspapers laterally off conveyor belt 1 , wherein they drop into a container not shown in the figure. It is also possible to place a suction opening instead of a fan 8, via which the leaflets and newspapers are suctioned away together with loose sheets still present. A combination is also possible wherein fan 8 blows the leaflets and newspapers laterally from conveyor belt 1 and wherein they come to lie in a suction opening placed opposite fan 8. Alternatively to or in combination herewith suction means (not shown) can be placed at least substantially centrally above conveyor belt 1. A suitable extractor device for this is known in the art. The leaflets and newspapers which have not been blown away laterally fall together with the magazines from the high outer end of conveyor belt 1 , wherein the magazines drop substantially into a container 5 and wherein leaflets and newspapers drop substantially into a container 6. Fig. 3 shows schematically an alternative embodiment of a device for separating leaflets, newspapers and magazines according to the invention, which corresponds wholly to the device shown in Fig. 2 but wherein an air knife 9 known in the art is mounted at the high outer end of conveyor belt 1 , which air knife can produce a powerful, narrow, upward directed airflow with a width substantially corresponding to the width of conveyor belt 1. Owing to this airflow leaflets, newspapers and magazines will begin to roll about at the moment they leave conveyor belt 1.
Especially for newspapers it is the case that they are folded open here, whereby the surface area increases significantly. A larger part of the newspapers will hereby come to lie in container 6. In the embodiment shown here air knife 9 is provided with a closing means 10 and a control 11 which feeds the air in the form of short pulses to air knife 9. Only a part of a leaflet, newspaper or magazine will hereby be struck in each case by the airflow, whereby the leaflets, newspapers and magazines will begin to roll about more violently.
Fig. 4 shows schematically a further alternative embodiment of a device for separating leaflets, newspapers and magazines according to the invention, which corresponds wholly to the device shown in Fig. 3 but wherein control 11 is provided with per se known detector 12 so that control 11 can detect that a leaflet, newspaper or magazine has reached the top side of conveyor belt 1. Control 11 can then send air to air knife 9 in the form of a short pulse at a moment such that a leaflet, newspaper or magazine is struck by this pulse at the position of either the front or rear side, whereby a maximum rolling-about can be realized and whereby an even larger part of the newspapers will drop into container 6.
Fig. 5 shows schematically a further alternative embodiment of a device for separating leaflets, newspapers and magazines according to the invention, which corresponds wholly to the device shown in Fig. 4 but wherein control 11 is provided with a row of per se known detectors 12a,b,c,d so that control 1 1 can detect that a leaflet, newspaper or magazine has reached the top side of conveyor belt 1. The air knife is formed by a row of per se known nozzles 9a,b,c,d. Control 11 can then send air in the form of a short pulse to one of the nozzles 9a,b,c,d at a moment such that either the front or the rear side of a leaflet, newspaper or magazine is struck by this pulse, whereby a maximum rolling-about can be realized with a minimum of compressed air and whereby an even larger part of the newspapers will drop into container 6.
An example of a suitable closing means 10 is a compressed air valve. Control means 11 can be realized in the form of suitable hardware, such as a
programmable logic controller, and associated dedicated software. It is noted that in some cases, with heavier mixtures of waste paper, effective rolling-about can be achieved by applying an air knife with a downward directed airflow which is placed higher than the high outer end of the conveyor belt.
The invention is of course not limited to the described and shown embodiment(s). The invention extends generally to any embodiment falling within the scope of protection as defined in the claims and as seen in the light of the foregoing description and accompanying drawings.